APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Comments and questions about the APOD on the main view screen.
User avatar
APOD Robot
Otto Posterman
Posts: 3453
Joined: Fri Dec 04, 2009 3:27 am

APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by APOD Robot » Sat Oct 29, 2011 4:06 am

Image Spiral Galaxy NGC 3370 from Hubble

Explanation: Is this what our own Milky Way Galaxy looks like from far away? Similar in size and grand design to our home Galaxy (although without the central bar), spiral galaxy NGC 3370 lies about 100 million light-years away toward the constellation of the Lion (Leo). Recorded above in exquisite detail by the Hubble Space Telescope's Advanced Camera for Surveys, the big, beautiful face-on spiral is not only photogenic, but has proven sharp enough to study individual stars known as Cepheids. These pulsating stars have been used to accurately determine NGC 3370's distance. NGC 3370 was chosen for this study because in 1994 the spiral galaxy was also home to a well studied stellar explosion -- a Type Ia supernova. Combining the known distance to this standard candle supernova, based on the Cepheid measurements, with observations of supernovas at even greater distances, has helped to reveal the size and expansion rate of the entire Universe itself.

<< Previous APODDiscuss Any APOD Next APOD >>
[/b]

User avatar
Beyond
500 Gigaderps
Posts: 6889
Joined: Tue Aug 04, 2009 11:09 am
Location: BEYONDER LAND

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by Beyond » Sat Oct 29, 2011 4:27 am

Well, nice, but i like the little bar in a bubble with the red streak on top, in the upper right, BETTER.
To find the Truth, you must go Beyond.

nstahl
Science Officer
Posts: 233
Joined: Mon Nov 29, 2004 4:08 am

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by nstahl » Sat Oct 29, 2011 5:08 am

I love this. It blows up really well.

I'm guessing that bubble-like galaxy(?) in the upper right is known and has probably been an APOD subject in the past.

User avatar
Ann
4725 Å
Posts: 9316
Joined: Sat May 29, 2010 5:33 am

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by Ann » Sat Oct 29, 2011 6:40 am

The release date of this Hubble image was September 4, 2003, so it is a golden oldie.

This is the sort of image whose color information I personally find a bit hard to read. In an RGB image, you would have expected to find red emission nebulae, which would have made it much easier to pin down where most of the star formation was taking place. Also, if you used broadband filters, the color variation over the face of NGC 3370 would probably have been greater, making it easier to judge the ages of the various stellar populations.

Of course this picture was made in order to identify individual Cepheid stars, which makes resolution a top priority. I don't know if a similar level of resolution could have been achieved with broadband filters.

My favorite link was one of the "NGC 3370" links, the one that is five lines down from the top and four lines up from the bottom. This link had a very nice zoom function.
Image
I searched the net for alternative images of NGC 3370, which might offer an alternative view of the color of NGC 3370. I searched in vain. Unfortunately, when Hubble has taken an image of a galaxy, this image is often seen as the "definite" image of this galaxy, so that no other pictures are needed. The thumbnail picture I'm posting here is one of the most "alternative" images I found.

Let me try, nevertheless, to describe the appearance of NGC 3370 in today's APOD. We may note that the yellow nucleus is small. Confusingly, the surrounding bulge is very ill-defined. The bulge can be identified in the zoom-in picture as the inner region where the individually discernible bright stars disappear. In the bulge, there is a "smooth population", which, confusingly, is quite similar in color to the outer arms. Both the outer arms, which are full of hot blue stars, and the smooth inner bulge, which consists of large numbers of evenly distributed faint to medium bright stars, are a sort of greenish-blue in color. The main color difference is that the greenish-blue hue is "clearer" in the outer arms, whereas it is "dirtier" and more mixed with dust in the bulge. Spiral dust lanes (or dust arcs) wind all the way down to the nucleus, and the bulge is full of these dust arcs.

It could be that NGC 3370 recently - say, perhaps, less than a billion years ago - formed a lot of stars in what is now the bulge. This vigorous star formation in the bulge region has now left behind copious amounts of F- and G-stars, which are responsible for the surprisingly non-yellow color of the bulge. (And speaking of "the bulge", by the way: the bulge seems perfectly flat to me, as if it isn't bulging at all.)

I'm glad this image of this galaxy could help Adam Riess, this years Nobel Prize winner in Physics (along with to other recipients) to pin down the expansion rate of the universe.

Ann
Color Commentator

User avatar
orin stepanek
Plutopian
Posts: 4636
Joined: Wed Jul 27, 2005 3:41 pm
Location: Nebraska

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by orin stepanek » Sat Oct 29, 2011 1:04 pm

Just another great galaxy; and this one similar in size to the Milky Way! 8-)
Orin

Smile today; tomorrow's another day!

Boomer12k
:---[===] *
Posts: 2411
Joined: Sun Apr 22, 2007 12:07 am

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by Boomer12k » Sat Oct 29, 2011 1:56 pm

Reminds me of a Net being thrown out to catch fish....

Wonder if there are fish there.....

:-----===== *

User avatar
neufer
Vacationer at Tralfamadore
Posts: 15735
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by neufer » Sat Oct 29, 2011 2:18 pm

Boomer12k wrote:
Reminds me of a Net being thrown out to catch fish....

Wonder if there are fish there.....
http://en.wikipedia.org/wiki/Thanks_for_all_the_fish
Art Neuendorffer

steeljam
Asternaut
Posts: 1
Joined: Sat Oct 29, 2011 2:26 pm

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by steeljam » Sat Oct 29, 2011 2:36 pm

I love the images that appear in APOD. Many images like the one here feature galaxies.
What I have a problem with understanding and imaging the scale.
When I look at the galaxy I can see starts and some misty stuff. But I know the stars must be something more and the mist is actually lots of stars.
Are there any visualisations that will 'zoom in' to show how the bright and misty stuff would resolve into stars and solar systems?

Tszabeau

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by Tszabeau » Sat Oct 29, 2011 2:37 pm

It makes me proud to live in such a handsome universe. Danged proud.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 15735
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by neufer » Sat Oct 29, 2011 2:51 pm

steeljam wrote:
What I have a problem with understanding and imaging the scale.
When I look at the galaxy I can see starts and some misty stuff. But I know the stars must be something more and the mist is actually lots of stars.
Are there any visualisations that will 'zoom in' to show how the bright and misty stuff would resolve into stars and solar systems?
Click to play embedded YouTube video.
Click to play embedded YouTube video.
Click to play embedded YouTube video.
Click to play embedded YouTube video.
Art Neuendorffer

biddie67
Science Officer
Posts: 483
Joined: Sun Jan 31, 2010 9:44 am
Location: Possum Hollow, NW Florida

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by biddie67 » Sat Oct 29, 2011 3:46 pm

The large version of this APOD is wonderful to study; not only for NGC 3370 but also for ALL the other galaxies that can be seen!!!

Ying-yangs the mind .....

drollere
Ensign
Posts: 73
Joined: Tue Aug 04, 2009 5:46 pm

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by drollere » Sat Oct 29, 2011 4:18 pm

this is a great topic, glad to see science interest win out with a pretty picture.

what is the trend in distance measurement? i think the estimated distance to the andromeda galaxy has been getting smaller, from the estimated 2 million light years distance i remember as a teenager to the circa 800K LY distance today. are the distances to galaxies within 1 billion LY generally getting revised downward, or upward, or are they narrowing around a constant average?

User avatar
Chris Peterson
Abominable Snowman
Posts: 14178
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by Chris Peterson » Sat Oct 29, 2011 4:33 pm

drollere wrote:what is the trend in distance measurement? i think the estimated distance to the andromeda galaxy has been getting smaller, from the estimated 2 million light years distance i remember as a teenager to the circa 800K LY distance today.
I think you might be confusing measurements in light years and measurements in parsecs. The distance to the Andromeda galaxy has been measured using different techniques, and all yield a distance of about 2.5 million light years- a value that hasn't changed substantially in quite a long while. That is about 780 kpc.

Without commenting on your age, I'd guess that distance measurement methods have improved considerably since you were a teenager (they certainly have since I was!), so the shift from 2 Mly to 2.5 Mly over (presumably) a few decades isn't too surprising. But I don't think there's a trend in distances in general.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

User avatar
Case
Commander
Posts: 580
Joined: Sat Jun 09, 2007 10:08 pm
Location: (52°N, 06°E)

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by Case » Sat Oct 29, 2011 4:49 pm

biddie67 wrote:The large version of this APOD is wonderful to study; not only for NGC 3370 but also for ALL the other galaxies that can be seen!
So many look approximately the same size. Perhaps there lies a busy cluster in that direction, partly covered by the foreground galaxy of NGC 3370.

User avatar
neufer
Vacationer at Tralfamadore
Posts: 15735
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Baade idea?

Post by neufer » Sat Oct 29, 2011 5:04 pm

Chris Peterson wrote:
drollere wrote:
what is the trend in distance measurement? i think the estimated distance to the andromeda galaxy has been getting smaller, from the estimated 2 million light years distance i remember as a teenager to the circa 800K LY distance today.
I think you might be confusing measurements in light years and measurements in parsecs. The distance to the Andromeda galaxy has been measured using different techniques, and all yield a distance of about 2.5 million light years- a value that hasn't changed substantially in quite a long while. That is about 780 kpc.

Without commenting on your age, I'd guess that distance measurement methods have improved considerably since you were a teenager (they certainly have since I was!), so the shift from 2 Mly to 2.5 Mly over (presumably) a few decades isn't too surprising. But I don't think there's a trend in distances in general.
http://en.wikipedia.org/wiki/Cepheid_variable_star wrote:

<<In 1922 Ernst Öpik presented a very elegant and simple astrophysical method to estimate the distance of M31. His result put the Andromeda Nebula far outside our Galaxy at a distance of about 1,500 Kly.

In 1924, Edwin Hubble established the distance to Classical Cepheid variables in the Andromeda Galaxy [to be ~900 Kly], and showed that the variables were not members of the Milky Way. That settled the Island Universe debate which was concerned with whether the Milky Way and the Universe were synonymous, or was the Milky Way merely one in a plethora of galaxies that constitutes the Universe.

In the 1940s, Walter Baade recognized that Cepheids actually consist of at least two separate populations (classical Cepheids & Type II Cepheids). Classical Cepheids are younger and more massive population I stars, whereas Type II Cepheids are older fainter population II stars. Classical Cepheids and Type II Cepheids follow different period-luminosity relationships. The luminosity of Type II Cepheids is, on average, less than classical Cepheids by about 1.5 magnitudes (but still brighter than RR Lyrae stars). Initial studies of Cepheid variable distances were complicated by the inadvertent admixture of classical Cepheids and Type II Cepheids. Walter Baade's seminal discovery led to a [doubling] in the distance to M31, and the extragalactic distance scale. >>
Last edited by neufer on Sat Oct 29, 2011 5:18 pm, edited 1 time in total.
Art Neuendorffer

neptunium

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by neptunium » Sat Oct 29, 2011 5:16 pm

Wonderful APOD! This galaxy reminds me of the Pinwheel galaxy at an angle. All those galaxies in the background make the image seem even more stunning. They are very colorful. I wonder if those galaxies in the background could qualify to be designated to be an Arp cluster?

This galaxy seems to have a high number of blue stars, seemingly young, in its arms. A few nebulae can be pointed out in them. The dust lanes in the galaxy are more apparent closer to its nucleus than in its arms. However, like Ann said, there does not seem to be a bulge in its nucleus, unlike the galaxies on the bottom and the upper right in this image.

Speaking of these other galaxies, there are a few in particular that I want to point out. There is one above the galaxy on the bottom of the image that has some sort of red ring around it. There is also another one to the right of said galaxy (not the red star) that has an odd spiral shape. There is one more galaxy to the left of the one on the upper right.

User avatar
Chris Peterson
Abominable Snowman
Posts: 14178
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: Baade idea?

Post by Chris Peterson » Sat Oct 29, 2011 5:44 pm

neufer wrote:Walter Baade's seminal discovery led to a [doubling] in the distance to M31, and the extragalactic distance scale.
Just because YOU were a teenager in the 1940s, don't assume the rest of us were! <g>
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

xuxa

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by xuxa » Sat Oct 29, 2011 7:41 pm

i just love shots like this not for the main subject but all the many other galaxys ect in the shot around it.. soo much more out there to see..as 2 the thing in the upper right, is that a galaxy forming?

User avatar
neufer
Vacationer at Tralfamadore
Posts: 15735
Joined: Mon Jan 21, 2008 1:57 pm
Location: Alexandria, Virginia

Re: Baade idea?

Post by neufer » Sat Oct 29, 2011 8:39 pm

Chris Peterson wrote:
neufer wrote:
Walter Baade's seminal discovery led to a [doubling] in the distance to M31, and the extragalactic distance scale.
Just because YOU were a teenager in the 1940s, don't assume the rest of us were! <g>
RR Lyrae, RR Lyrae, pants on fire :!:
Art Neuendorffer

User avatar
Ann
4725 Å
Posts: 9316
Joined: Sat May 29, 2010 5:33 am

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by Ann » Sat Oct 29, 2011 9:01 pm

xuxa wrote:i just love shots like this not for the main subject but all the many other galaxys ect in the shot around it.. soo much more out there to see..as 2 the thing in the upper right, is that a galaxy forming?
Good question, xuxa. I agree that it looks kind of amazing.

I'd say we are looking at a barred galaxy, a galaxy with an elongated, cigar-shaped "body". The bar of this galaxy is very yellow and bright. Clearly it contains billions upon billions of old red and yellow stars. The bar of the galaxy is superimposed on a disk, which is also yellow in color but not quite so bright. The disk can also be thought of as a ring, because many barred galaxies have a ring surrounding their bars.

However, this yellow galaxy also has two or possibly three long thin arms. The arm farthest to the right appears mostly smooth, faint and non-blue, but the two other arms contain clusters and concentrations of young blue stars.

I think the barred yellow galaxy may be interacting with the very white spiral galaxy to the lower left of it. Note that this spiral galaxy appears quite similar to NGC 3370, although it is whiter in color. That, however, may be a consequence of redshift, since the white spiral is definitely much farther away from us than NGC 3370, so it has had its light "stretched" a lot more by the expansion of the universe.

That bright red galaxy that seems to be interacting with the barred yellow galaxy is undoubtedly much farther away. Its red color is a sure sign that the light from this galaxy has been a lot more redshifted than the light from the yellow barred galaxy and the white spiral, and cosmic expansion is the only thing that could shift the light from this galaxy so far into the red part of the spectrum. So compared with the yellow barred galaxy and the white spiral, the red edge-on galaxy is a background object.

Ann
Color Commentator

User avatar
Chris Peterson
Abominable Snowman
Posts: 14178
Joined: Wed Jan 31, 2007 11:13 pm
Location: Guffey, Colorado, USA

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by Chris Peterson » Sat Oct 29, 2011 9:17 pm

Ann wrote:This is the sort of image whose color information I personally find a bit hard to read. In an RGB image, you would have expected to find red emission nebulae, which would have made it much easier to pin down where most of the star formation was taking place. Also, if you used broadband filters, the color variation over the face of NGC 3370 would probably have been greater, making it easier to judge the ages of the various stellar populations.
The high dynamic range in this image was obtained primarily using a wideband green filter, which is standard for photometry. Some additional data was obtained using a wideband IR filter, mainly a used as a calibration tool. Then, less deep wideband blue data from a completely different project was incorporated, allowing for an approximate (but far from perfect) "true color" reconstruction.
Chris

*****************************************
Chris L Peterson
Cloudbait Observatory
http://www.cloudbait.com

BoatsBM1
Asternaut
Posts: 2
Joined: Sat Oct 09, 2010 8:13 pm

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by BoatsBM1 » Sat Oct 29, 2011 11:21 pm

This was posted back on 12 October 2008 with the same explanation;

http://apod.nasa.gov/apod/ap081012.html

neptuniun

Re: APOD: Spiral Galaxy NGC 3370 from Hubble (2011 Oct 29)

Post by neptuniun » Sat Oct 29, 2011 11:56 pm

Ann wrote:The bar of the galaxy is superimposed on a disk, which is also yellow in color but not quite so bright. The disk can also be thought of as a ring, because many barred galaxies have a ring surrounding their bars.
Well, that pretty much answers my question about that red-ringed galaxy. Thanks!